(1) Field of the Invention
The present invention relates generally to elastic web fabric and, more particularly, to an elastic web fabric with bidirectional stretch suitable for use in orthopedic wrap and athletic supporter pouch fabric.
(2) Description of the Prior Art
Most elastic web fabric manufactured for use in garments such as athletic supporter pouch fabrics are currently produced on a Lamb knitting machine which is a V-bed knitting machine originally developed in the 1920""s to produce sweater collars. Such machines operate between 75-100 rpms producing only one piece of fabric per machine. Accordingly, to produce any substantial amount of fabric requires a number of machines operating continuously. On the other hand, modern crochet knitting machines operate substantially faster. For example, a crochet knitting machine can operate as high as 1100 or higher rpm which is over 10 times faster than a Lamb V-bed machine and, at the same time, can produce multiple fabric pieces.
One particularly well-known crochet machine is a Comez 800 Series flat bed knitting machine. While originally introduced in 1977 as the model 805 machine, it has evolved to the model 814 and now is known as the model 816 machine. This machine is available from Comez Machinery of Cilavegna, Italy. However, this machine uses bearded needles because at over about 1100 rpms, latch needles become inoperable. Such needles are not suitable for knitting large diameter elastic yarns as required for the present invention. In addition, material produced on such a machine normally does not have stretch in both the x and y directions and, like most knitted elastomeric material, the edges of the fabric curls.
Thus, there remains a need for a new and improved elastic web knitted fabric and method for producing the same which has bi-directional stretch, is curl-free and ravel resistant and, at the same time, can be produced at a substantially increased rate over conventional V-bed knitting machines and also produce multiple fabric pieces.
The present invention is directed to an elastic web fabric and method for producing the same which is curl-free and has bi-directional stretch of between about 50-125% stretch in the width direction and 50-200% stretch in the length direction. In the preferred embodiment, the fabric includes a center marker formed from a two-needle shift of two rubbers to provide a centering ,line to aid in assembly of a finished article. Also, in the preferred embodiment, the left top edge of the fabric has about six rubbers and the right top edge has about 5 rubbers to prevent curling to produce a fabric which is more easily cut and fabricated into the finished article.
The fabric according to the present invention is knit on an improved crochet knitting machine normally having bearded needles. The improvement includes replacing the bearded needles with latch needles and adding a latch guide adjacent to the latch needles. A tricot cam is also installed. Finally, the lobes located in the guide pattern wheel of the machine are lengthened to increase the dwell time to prevent two-needle run-on during knitting.
The fabric according to the present invention includes an unique sequence. A first bar of weft yarn, which is the back bar, uses a 1-3/1-3 stitch and moves over two needles and repeats. A second bar, which is the rubber, uses a 1-1/2-2 movement, two on one side of the needle and two on the other side. A third bar of weft yarn, which is the front bar, uses a 1-3/1-5 stitch to prevent weft yarn slippage. The fourth bar, which is the warp yarn, uses a tricot cam which uses an 0-1/1-2 stitch to give a lock stitch chain pattern.
Accordingly, one aspect of the present invention is to provide an improved crochet knitting machine normally having bearded needles. The improvement includes: (a) replacing the bearded needles with latch needles; (b) adding a latch guide adjacent to the latch needles; (c) installing a tricot cam; and (d) lengthening the lobes located in the guide pattern wheel of the machine to increase the dwell time to prevent two-needle run-on during knitting.
Another aspect of the present invention is to provide a knitted elastic fabric. The fabric includes: (a) a first bar of weft yarn, which is the back bar, and uses a 1-3/1-3 stitch and moves over two needles and repeats; (b) a second bar, which is the rubber, and uses a 1-1/2-2 movement, two on one side of the needle and two on the other side; (c) a third bar of weft yarn, which is the front bar, and uses a 1-3/1-5 stitch to prevent weft yarn slippage; and (d) a fourth bar, which is the warp yarn, and uses a tricot cam which uses an 0-1/1-2 stitch to give a lock stitch chain pattern.
Still another aspect of the present invention is to provide a knitted elastic fabric. The fabric being curl-free and having bi-directional stretch of between about 50-125% stretch in the width direction and 50-200 stretch in the length direction.